Apex domains cannot have CNAME records.
Question and response
Question
dig eneroc.fi. NS
Answer
eneroc.fi. 5 NS ns3.eneroc.net.
eneroc.fi. 5 NS dns.gbooker.net.
eneroc.fi. 5 NS dns6.nettivaraus.com.
eneroc.fi. 5 NS ns4.eneroc.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0